[news.eclipse.tools.emf] Re: [CDO] CDOSavePoint and rollback question

[Sebastian Paul <sebastian.paul.ext@xxxxxxxxxxx>]

Hello Kai,
> Yes, that is what I meant. I am designing my app at the moment for 
> single user, but keep a multi user setup in the back of my mind.
> CDO makes this very easy, but it also has many advantages for single 
> user applications.
> I use the rollback for example to undo all changes of a bigger model 
> that is modified by a large wizard dialog when the cancel button is 
> pressed.
I exercised a small example with a CDO model, a view that displays model 
data and a wizard that adds or modifies data. As you certainly do, my 
wizard creates a CDOSavePoint hen it is initialized. When the wizard is 
canceled, the transaction is rolled back to the savepoint. When the 
wizard performs finish, the transaction is committed. As wizard 
modifications of the model would trigger UI updates in the view, I open 
a separate transaction from where I retrieve model objects that are 
passed to the wizard. All modifications are isolated until the wizard 
commits the transaction. After the wizard dialog is closed, the wizard 
transaction is closed, regardless of the dialog's return code.

My application used CDO with a JVMConnector and MemStore. Committing a 
transaction does not mean that the document is actually saved. In 
applications where commit is equivalent to saving the document, above 
approach would not be appropriate. A real nested, isolated transaction 
would be fine for that, but I don't think CDO will support that.

Kind regards, Sebastian